MEMPHIS, Tenn.—Coach Larry Brown has endured more than he cares of his SMU Mustangs' inability to handle adversity.

And the No. 25 Mustangs showed the problems again Thursday leading to their departure in the quarterfinals of the American Athletic Conference tournament.

The Mustangs let a double-digit lead in the second half slip away as poor shooting allowed Houston to upset SMU 68-64.

SMU converted one of its five second-half field goals early for a 42-32 lead. From there, SMU collapsed, allowing Houston to go on a 19-4 run and avenge two regular season losses to the tournament's No. 3 seed.

"I'm just disappointed because the same stuff happens over and over again," Brown said. "Things don't always go right. It's how you handle situations that I'm concerned about."

Cannen Cunningham led SMU (23-9), the tournament's third seed, with 14 points, while Markus Kennedy scored 13 and had nine rebounds. Nick Russell had 10 points.

Nic Moore, SMU's leading scorer at 13.9 a game, had eight points, but missed all nine of his shots from the field. He had eight assists.

SMU has dropped its last three games, including losses to No. 5 Louisville and No. 19 Memphis before Thursday's defeat by Houston. Brown had expressed his displeasure after the Memphis loss in his team's inability to handle games when situations turned against them.

"I kind of had in my gut what was going to happen," Brown said of Thursday's loss. "Houston, I felt, thought they could win. I was thrilled the way we finished the (first) half. Kind of felt we started to understand that every possession matters and every possession defensively is important. Again, we didn't handle it."

Jherrod Stiggers scored 19 points, including five 3-pointers, to lead the Cougars.

"My mindset was (you) never know if this would be the last game," Stiggers said. "Never know (if) there would be a tomorrow, so leave everything on the floor. Take everything they give me."

The Cougars (17-15), who will face either No. 5 Louisville or Rutgers, which play later Thursday, converted 9 of 19 3-pointers in the game.

L.J. Rose finished with 16, hitting all three of his shots from outside the arc. TaShawn Thomas added 14 points, nine rebounds and four blocks, including a key one down the stretch, while Danuel House finished with 11 for the sixth-seed Houston.

The Mustangs were within 64-61 when Kennedy went inside, but was blocked by Thomas, his fourth of the game, with about 17 seconds left and Houston held on from there.

Houston's run included five points from Thomas and Rose, Stiggers and Danuel House making 3-pointers.

The Cougars went up 51-46 lead and Brown took a timeout. The Houston lead would eventually reach 55-47.

"I knew they wasn't going to give up," Russell said of Houston, adding: "We said we had to come out and win the first five minutes, but they came out stronger than us."

SMU scratched back to make it 55-52 when Kennedy fell under the Mustang basket holding his right ankle. While he was down, Richardson scored on the other end for Houston for a 57-52 lead.

Kennedy returned, and the Mustangs would get within two points on a couple of occasions, but could never overtake Houston.

"This is just part of our building process," Brown said. "We have to develop a trust factor in one another and I don' think we've gotten there yet."